Arrangement of a movable fork of a stacking crane or the like

ABSTRACT

On a fork carrier of a stacking crane, a load supporting fork is movable on either side of the fork carrier between an extended position and a retracted position. Movement is directed by a parallelogram linkage connecting the fork to a linearly moving guide element on the fork carrier. Control levers connected to the fork carrier assure the movement of the fork between the two positions as the guide element moves on the fork carrier.

United States Patent [1113,567,055

[72] Inventors SergePreto; [56] References Cited Rwnus Kjolen, Bergen, Norway UNITED STATES PATENTS 3; Qf J- 2 2 2,181,881 12/1939 Ferris 214/148 t d 3,061,118 10/1962 Halberstadt.. 214/146.5X 3,154,208 10/1964 1361161 11.--- 214/730 [73] Assignee Sverre MunckA/S Bergen, Norway FOREIGN PATENTS 32] Priority Oct. 12,1967 987,637 3/1965 01661131166111 214/730 [33] Numay Primary Examiner-Gerald M. Forlenza L3 l 1 l70l l 1 Assistant Examiner-Raymond B. Johnson [54] ARRANGEMENT OF A MOVABLE FORK OF A 660, 670, 700, 701 701 (B), 701 (D), (Digest), 146.5,148,16.42, 16.4

Attorney-Larson and Taylor ARRANGEMENT or A MOVABLE FORK OF A STACKING CRANE on THE LIKE The present invention relates to an arrangement of a movable fork for stacking cranes or the like for the displacement of loading pallets. V

Whencranes having a movable loading fork are used in storing rooms or the like, the fork has to be made movable relative to the crane in. order to reduce the passages between the pallet shelves to a minimum. This movement should be so extensive as to permit the pallet to be pulled out of the shelves. In known embodiments of this kind of movable fork for stacking cranes, the fork has been mounted on a horizontally movable slide operated by a screw. Due to the extension of the slide and mounting of the driving means the movability of the fork is, however, so restricted that the pallet has to be taken out of the shelves in a two-step movement. This makes the operation time consuming and complicated.

The object of the present invention is thus to accomplish a suspension arrangement of a fork for displacing loading pallets, which suspension arrangement renders it possible to pull the pallet from a shelf in one single and quick operation.

Furthermore, the new suspension arrangement of the fork on the fork carrier is suggested to be designed in such a way that the fork can operate at the desired one of the two sides of the fork carrier. The above objects are achieved by an arrangement,: characterized in that the. rear end of the fork is furnished with a head or the like providing a pivot bearing for one end of an arm parallelogram, the other end of which is pivoted to an element, that by suitable guiding means can be displaced relative to the fork carrier, control and power means being arranged to swing the head of the fork in towards and pastthe fork carrier or out intoapallet gripping position respectively as the element is displaced, within its guiding means. i I

According to another feature of the invention the fork can be swung 90 on an axis through its head in order to be operable on the desired side of the fork carrier.

The mentioned control and power means may preferably consist of an arm, one end of which is pivoted to the said arm parallelogram 'and the other end of which is power driven and pivoted to the fork carrier.

The invention is described in detailin the following in connection with an embodiment diagrammatically shown in the accompanying drawing.

FIG. 1 shows a side elevation of the arrangement, and

FIGJZ shows a front elevation taken in the direction of the arrows a in FIG. 1.

The fork carrier 1 constituting the hoistable part of the crane, runs in guides on the crane posts in a manner known per se. The pallet fork comprises teeth 2, 3 with a mutual angle of 90 and is mounted on the fork head 4 so as to permit the teeth to be optionally swung 90. In this way the fork is operable on the desired one of the two sides of the fork carrier 1 The fork head 4 is suspended on the parallel and equally long arms 5 and 6. The opposite ends of these arms 'are head swings between the two said positions.

'tioned, this power arm at one end is pivoted to the center of the arm 6, while its other end is power driven and secured to the fork carrier. Power istransmitted from a motor 9 by a chain drive and gear transmissions. When the arm 8 is moved from left to right in FIG. 1 the fork due to its suspension on the parallel arms 5, 6 will experience a precise horizontal displacement from the position A to the position B.

The expert will immediately understand that the embodiments shown in the drawing and described above can be modified in severalways within the scope of the invention. The main idea is that the fork 2, 3 by its suspension on the fork carrier 1 obtains a arallel displacable support which at the same time secures t e necessary lifting movement for the dlS- placement of a loading pallet e.g. from a storing shelfto a position ready for transport and vice versa.

We claim: I

I. An apparatus for manipulating a load supporting fork of a stacking crane comprising, a fork carrier adapted to be lifted and lowered along guides in a crane post, vertically extending guide surfaces formed on said fork carrier, a guide element mounted on said fork carrier for vertical movement along said guide surfaces, a load supporting fork having a generally horizontal load supporting surface, a fork head connected to the fork, a parallelogram linkage comprising a pair of parallel links, each pivotally connected at one end to the guide element and at the other end to the fork' head, and a control means operative connected to the parallelogram linkage to control movement of the same, relative to the fork carrier, such that as the guide element moves vertically along said guide surfaces, thefork head moves in a horizontal path in a direction transverse to the said pivot axis between two positions located on opposite sides of the said pivot connection of the parallelogram linkage to the guide element, while retaining the load supporting surface generally horizontal, whereby inone of said positions, the fork extends outwardly from the fork carrier to receive a load, and in the other position the fork is located closer to the fork carrier, said control means comprising a control arm pivotally connected at one end to the parallelogram linkage and at the other end to the fork carrier, such that as the guide element moves vertically, the fork 2. An apparatus according to claim 1 including means arranged to move said fork head between the two said mounted on a slide, or guide element 7 running in vertical guides 10. The fork can be-moved because its arms 5, 6 are positions.

3. An apparatus according to claim 2, wherein said control means comprises a control arm pivotally connected to the parallelogram linkage and to the fork carrier, and wherein said power means is connected to the said control arm to turn the same about its connection to the fork carrier to swing the parallelogram linkage, and hence the fork head between the two said positions.

4. An apparatus according to claim I, wherein the said load supporting surface of the fork extends horizontally outwardly from said fork head, and including a :second load supporting surface extending upwardly from said fork head, and wherein the fork can be swung about an axis through said fork head such that the second load supporting surface of the fork extends horizontally in a direction opposite from the first said load supporting surface when the latter is in its generally horizontal position.

a power 

1. An apparatus for manipulating a load supporting fork of a stacking crane comprising, a fork carrier adapted to be lifted and lowered along guides in a crane post, vertically extending guide surfaces formed on said fork carrier, a guide element mounted on said fork carrier for vertical movement along said guide surfaces, a load supporting fork having a generally horizontal load supporting surface, a fork head connected to the fork, a parallelogram linkage comprising a pair of parallel links, each pivotally connected at one end to the guide element and at the other end to the fork head, and a control means operative connected to the parallelogram linkage to control movement of the same, relative to the fork carrier, such that as the guide element moves vertically along said guide surfaces, the fork head moves in a horizontal path in a direction transverse to the said pivot axis between two positions located on opposite sides of the said pivot connection of the parallelogram linkage to the guide element, while retaining the load supporting surface generally horizontal, whereby in one of said positions, the fork extends outwardly from the fork carrier to receive a load, and in the other position the fork is located closer to the fork carrier, said control means comprising a control arm pivotally connected at one end to the parallelogram linkage and at the other end to the fork carrier, such that as the guide element moves vertically, the fork head swings between the two said positions.
 2. An apparatus according to claim 1, including a power means arranged to move said fork head between the two said positions.
 3. An apparatus according to claim 2, wherein said control means comprises a control arm pivotally connected to the parallelogram linkage and to the fork carrier, and wherein said power means is connected to the said control arm to turn the same about its connection to the fork carrier to swing the parallelogram linkage, and hence the fork head between the two said positions.
 4. An apparatus according to claim 1, wherein the said load supporting surface of the fork extends horizontally outwardly from said fork head, and including a second load supporting surface extending upwardly from said fork head, and wherein the fork can be swung 90* about an axis through said fork head such that the second load supporting surface of the fork extends horizontally in a direction opposite from the first said load supporting surface when the latter is in its generally horizontal position. 